Led bar, switches and harnesses

Hi.
I currently have a boomslang loom on my 300tdi.

I want to put a led bar on the roof and have seen a ready made loom that has relay, fuse etc and gets switch for full beam from the headlight plug and like the boomslang gives a new plug for headlamp.

I am assuming it’s not recommended to use both at same time? What about if led bar is plugged into RHS only.

finally if I wanted the light bar controlled by a switch and then the full beam switch (ie can choose not to have it on) I assume I wire the switch in the headlamp feed.
Thanks

Landy_Ben said:

Hi.
I currently have a boomslang loom on my 300tdi.

I want to put a led bar on the roof and have seen a ready made loom that has relay, fuse etc and gets switch for full beam from the headlight plug and like the boomslang gives a new plug for headlamp.

I am assuming it’s not recommended to use both at same time? What about if led bar is plugged into RHS only.

finally if I wanted the light bar controlled by a switch and then the full beam switch (ie can choose not to have it on) I assume I wire the switch in the headlamp feed.
Thanks

Click to expand...

Yes you would wire the relay feed from the headlight (main beam) live through the extra switch. If you want to keep them off, open the switch.

Edit: I’m not sure about the boomsland harness and connecting the extra harness to it. In theory, both auxiliary harness should only be triggering relays, so using milliamps. If that’s the case, connecting them to the same side shouldn’t be an issue.

Thanks.

Hi thanks for the help so far. Been doing some reading off older posts and the hilux spotlight wiring page that gets referenced.

wiring front led bar and rear work lights (separately)

I think what I need for each is

1. 12v fused from battery To relay.
2. Trigger wire from reversing lights or headlights main beam to relay
3. Ground from relay to suitable ground
4. Feed of 12v to lights from relay
5. Ground from lights to suitable ground

I want to be able to switch rear work lights on without putting in gear so I assume I need another trigger 12v feed to relay with a switch in so when on it turns on lights without being in reverse.

I want to be able to turn led bar off when main beams are on sometimes. So I assume in this case the switch is in the ground from relay


Does that sound right?
Am I over complicating it by wanting to turn led bar off? I may never want to turn it off.

Landy_Ben said:

Hi thanks for the help so far. Been doing some reading off older posts and the hilux spotlight wiring page that gets referenced.

wiring front led bar and rear work lights (separately)

I think what I need for each is

1. 12v fused from battery To relay.
2. Trigger wire from reversing lights or headlights main beam to relay
3. Ground from relay to suitable ground
4. Feed of 12v to lights from relay
5. Ground from lights to suitable ground

I want to be able to switch rear work lights on without putting in gear so I assume I need another trigger 12v feed to relay with a switch in so when on it turns on lights without being in reverse.

I want to be able to turn led bar off when main beams are on sometimes. So I assume in this case the switch is in the ground from relay


Does that sound right?
Am I over complicating it by wanting to turn led bar off? I may never want to turn it off.

Click to expand...

Personally, I don’t like earth switching. If you get a short to earth, before the switch, the switch becomes useless.

Start with the reverse circuit. If you want to switch the lights on from two sources, I would use a 5 pin changeover relay. The relay has a normally closed state, and a switched state. So the reverse light feed goes to the normally closed side of the relay, the reverse lights will power the rear LEDs. If you want to turn them on manually, switch the switch and the relay changes state to a battery live, and the lights come on. The reverse light won’t come on as the relay is effectively open to that circuit. You could also use a standard relay, but that will mean using diodes to stop current flowing “in the wrong direction” through the circuit.

If you want to be able to use main beam without the spot lights, just place the switch is the feed line from the main beam. With main beam off, the spots are off. Switch main beam on, and the new switch off, spot lights off. Main beam on, new switch on, spots on.

Landy_Ben said:

Hi thanks for the help so far. Been doing some reading off older posts and the hilux spotlight wiring page that gets referenced.

wiring front led bar and rear work lights (separately)

I think what I need for each is

1. 12v fused from battery To relay.
2. Trigger wire from reversing lights or headlights main beam to relay
3. Ground from relay to suitable ground
4. Feed of 12v to lights from relay
5. Ground from lights to suitable ground

I want to be able to switch rear work lights on without putting in gear so I assume I need another trigger 12v feed to relay with a switch in so when on it turns on lights without being in reverse.

I want to be able to turn led bar off when main beams are on sometimes. So I assume in this case the switch is in the ground from relay


Does that sound right?
Am I over complicating it by wanting to turn led bar off? I may never want to turn it off.

Click to expand...

Have a read of this for more info on different types of relays.
https://www.12voltplanet.co.uk/relay-guide.html

considering MOTs shouldn't any auxiliary lights be on a separate switch and not come on with main beam?

gymmaniac said:

considering MOTs shouldn't any auxiliary lights be on a separate switch and not come on with main beam?

Click to expand...

No. Any “auxiliary” lights should extinguish with main beam being turned off. It’s in the vehicle lighting regs.

mick 1986 said:

Personally, I don’t like earth switching. If you get a short to earth, before the switch, the switch becomes useless.

Start with the reverse circuit. If you want to switch the lights on from two sources, I would use a 5 pin changeover relay. The relay has a normally closed state, and a switched state. So the reverse light feed goes to the normally closed side of the relay, the reverse lights will power the rear LEDs. If you want to turn them on manually, switch the switch and the relay changes state to a battery live, and the lights come on. The reverse light won’t come on as the relay is effectively open to that circuit. You could also use a standard relay, but that will mean using diodes to stop current flowing “in the wrong direction” through the circuit.

If you want to be able to use main beam without the spot lights, just place the switch is the feed line from the main beam. With main beam off, the spots are off. Switch main beam on, and the new switch off, spot lights off. Main beam on, new switch on, spots on.

Click to expand...

Thank you

mick 1986 said:

No. Any “auxiliary” lights should extinguish with main beam being turned off. It’s in the vehicle lighting regs.

Click to expand...

Thanks so the way I want to do it is fine because it can only come on with the main beam but I can choose not to.

mick 1986 said:

Personally, I don’t like earth switching. If you get a short to earth, before the switch, the switch becomes useless.

Start with the reverse circuit. If you want to switch the lights on from two sources, I would use a 5 pin changeover relay. The relay has a normally closed state, and a switched state. So the reverse light feed goes to the normally closed side of the relay, the reverse lights will power the rear LEDs. If you want to turn them on manually, switch the switch and the relay changes state to a battery live, and the lights come on. The reverse light won’t come on as the relay is effectively open to that circuit. You could also use a standard relay, but that will mean using diodes to stop current flowing “in the wrong direction” through the circuit.

If you want to be able to use main beam without the spot lights, just place the switch is the feed line from the main beam. With main beam off, the spots are off. Switch main beam on, and the new switch off, spot lights off. Main beam on, new switch on, spots on.

Click to expand...

So with this relay am I right in thinking 30 goes to the lights87a to reversing light, 87 to switch what. Is connected to 86 and 85? Thanks

Landy_Ben said:

So with this relay am I right in thinking 30 goes to the lights87a to reversing light, 87 to switch what. Is connected to 86 and 85? Thanks
View attachment 220907

Click to expand...

No. 85 and 86 are the coil, so this is what switches the relay “on or off” (actually closed and open). If you want to use this relay in the reverse light circuit, then you would wire it like this:
85 to earth or reverse light feed
86 to reverse light feed or earth (opposite of 85)
30 to battery pos via suitable fuse
87 to the rear work lights.

If you want to use this with a second feed to turn them on via a switch, then you need to use a diode on the reverse light feed, and put a second feed to the same connector, also with a diode.

Edit: After reading back through my posts, now I understand why you linked to that relay. yes you can use that relay in the way you describe, but not using the contacts as you have wrote.

85 and 86 would need to be wired to your switch (the one which would turn on the aux lights without reverse) and an earth. This would cause the relay to switch over from open to closed, so from 87a to 87.
87 would be connected to battery pos via a suitable fuse.
87a would be connected to the reverse light feed.
30 would be connected to the rear aux lights.

The only problem I can see is that the LEDs may be too high a current draw for the standard reverse circuit, but you could speck LEDs that aren’t too high a current and it would work fine.

mick 1986 said:

No. 85 and 86 are the coil, so this is what switches the relay “on or off” (actually closed and open). If you want to use this relay in the reverse light circuit, then you would wire it like this:
85 to earth or reverse light feed
86 to reverse light feed or earth (opposite of 85)
30 to battery pos via suitable fuse
87 to the rear work lights.

If you want to use this with a second feed to turn them on via a switch, then you need to use a diode on the reverse light feed, and put a second feed to the same connector, also with a diode.

Edit: After reading back through my posts, now I understand why you linked to that relay. yes you can use that relay in the way you describe, but not using the contacts as you have wrote.

85 and 86 would need to be wired to your switch (the one which would turn on the aux lights without reverse) and an earth. This would cause the relay to switch over from open to closed, so from 87a to 87.
87 would be connected to battery pos via a suitable fuse.
87a would be connected to the reverse light feed.
30 would be connected to the rear aux lights.

The only problem I can see is that the LEDs may be too high a current draw for the standard reverse circuit, but you could speck LEDs that aren’t too high a current and it would work fine.

Click to expand...

Mick thank you very much. Useful to be able to learn and ask questions. Ben

Landy_Ben said:

Mick thank you very much. Useful to be able to learn and ask questions. Ben

Click to expand...

No problem. Make sure you check the rating of the lights, and ask questions if your not entirely sure what you are doing. It’s better to ask what seems like a stupid question, than it is to set fire to the vehicle because something was wired up wrong.

mick 1986 said:

No problem. Make sure you check the rating of the lights, and ask questions if your not entirely sure what you are doing. It’s better to ask what seems like a stupid question, than it is to set fire to the vehicle because something was wired up wrong.

Click to expand...

So in this scenario

85 and 86 would need to be wired to your switch (the one which would turn on the aux lights without reverse) and an earth. This would cause the relay to switch over from open to closed, so from 87a to 87.
87 would be connected to battery pos via a suitable fuse.
87a would be connected to the reverse lightfeed.
30 would be connected to the rear auxlights.


I need power switched by the switch to energise the relay to switch is that right?

Landy_Ben said:

So in this scenario

85 and 86 would need to be wired to your switch (the one which would turn on the aux lights without reverse) and an earth. This would cause the relay to switch over from open to closed, so from 87a to 87.
87 would be connected to battery pos via a suitable fuse.
87a would be connected to the reverse lightfeed.
30 would be connected to the rear auxlights.


I need power switched by the switch to energise the relay to switch is that right?

Click to expand...

Yeah, that all sounds right to me. Check the actual relay you buy, just in case the terminals are wired up differently, but for the relay in the photo, yes that is correct.

Edit: what rating are the lights you are trying to use as aux lights?

mick 1986 said:

Yeah, that all sounds right to me. Check the actual relay you buy, just in case the terminals are wired up differently, but for the relay in the photo, yes that is correct.

Edit: what rating are the lights you are trying to use as aux lights?

Click to expand...

Hi at the front it is a 300w 50” led lightbar.

At the back it is 2x 27w led lights

Landy_Ben said:

Hi at the front it is a 300w 50” led lightbar.

At the back it is 2x 27w led lights

Click to expand...

If it is 300W, then P=I*V, so 300W = I * 13V. Transpose for I =P/V so 300/13 = roughly 23A. That’s no problem and doesn’t really need a bigger alternator.

The two reverse ones will be a problem. I think your only allowed something like 21W of reverse light power. They will need to be able to be turned off for MOT. Also, you can wire these in as we discussed, straight through the relay and original wiring. Using the formula above, you end up with a working current of around 4A.

Thanks Mick. Yes for MOT I thought I’d pull the reversing light feed.